Klaviyo is looking for a Senior Security Engineer to add to our growing Detection & Response Team. This is an engineering role that spans the full detection and response lifecycle - leveraging software development practices to build detections, triaging alerts, lead investigations, respond to incidents, perform threat hunting, and build the tooling that keeps us from doing the same work twice. As a member of the team, you will have the opportunity to work on complex large-scale security challenges across Klaviyo's enterprise, cloud, and product environments, and shape how an engineering-first D&R function uses automation and AI in production, at scale, alongside talented and ambitious colleagues spanning multiple regions and timezones.

How you will make a difference:

• Leverage engineering practices to develop, test, and deploy high-fidelity rule-based and anomaly-based detections-as-code
• Detect and respond to cyber threats using security data lake, SIEM, and cloud platforms
• Respond to alerts, cyber threats, and drive end-to-end incident response investigations
• Perform digital forensic investigations to include collection and analysis of evidence
• Automate and codify detection and response workflows and processes
• Build security tooling to drive automation across D&R lifecycle
• Improve and maintain detection and response pipelines and underlying systems
• Work with our Threat Intelligence team to identify and respond to sophisticated threats
• Develop AI-first security systems to automate detection and response operations
• Conduct threat hunts across corporate, cloud and product environments
• Support data engineering workflows for core security data lake and SIEM platforms
• Be an active member of D&R on-call rotations
• Coach and mentor security engineers within the detection & response team

We'd love to hear from you if you have:

• 5+ years of hands-on security experience in modern cloud environments
• Experience in triaging and responding to cyber threats
• Experience in large-scale log analysis, incident response and/or digital forensics
• Experience with centralized security data lakes and SIEM solutions
• Hands-on experience in writing detections-as-code
• Solid data querying skills (e.g. SQL, Splunk)
• Familiarity with large-scale data pipelines and data engineering techniques
• Proficient in programming languages to automate / build (e.g., Python, Go or similar)
• Proven experience with git/GitHub and CI/CD automations
• Familiarity with tactics, techniques, and procedures used by threat actors
• Experience being part of detection and response or incident response on-call
• Engineering-first and AI-first approach for all work performed
• Strong passion for continuous learning and staying updated on evolving technology
• Strong oral and written communication skills
• Team player with a strong, self-managing work ethic

Massachusetts Applicants:It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Our salary range reflects the cost of labor across various U.S. geographic markets. The range displayed below reflects the minimum and maximum target salaries for the position across all our US locations. The base salary offered for this position is determined by several factors, including the applicant's job-related skills, relevant experience, education or training, and work location.

In addition to base salary, our total compensation package may include participation in the company's annual cash bonus plan, variable compensation (OTE) for sales and customer success roles, equity, sign-on payments, and a comprehensive range of health, welfare, and wellbeing benefits based on eligibility.

Your recruiter can provide more details about the specific salary/OTE range for your preferred location during the hiring process.

Base Pay Range For US Locations:

$141,600-$212,400 USD

This role may require up to 10% travel for purposes such as new hire onboarding, client or partner work if applicable, team meetings, and industry events. Travel is coordinated in advance.